Air treating and conditioning apparatus



July 4, 1967 REEN 3,328,941

AIR TREATING AND CONDITIONING APPARATUS Original Filed July 24, 1963 7Sheets-Sheet 1 INVENTOR 64422940 [6255 /g' 7. BY

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Original Filed July 24, 1963 AIR TREATING AND CONDITIONING APPARATUS 7Sheets-Sheet 2 A T TORNEX July 4, 1967 H. F. GREEN 3,328,941

AIR TREATING AND conmnoumc APPARATUS Original Filed July 24, 1963 7Sheets-Sheet Z INVEN TOR.

6%?010 F. GPEf/V BY July 4, 1967 H. F. GREEN 3,328,941

AIR TREATING AND CONDITIONING APPARATUS Original Filed July 24, 1965 7Sheets-Sheet 4 I l I I I I l I I INVENTOR. HAROLD F. 6REE/V BY ATTORNEY.

July 4, 1967 H. F. GREEN 3,328,941

AIR TREATING AND CONDITIONING APPARATUS Original Filed July 24, 1963 7Sheets-Sheet 5 INVENTOR. HA/POAO f. AEEN ATTORNEY.

July 4, 1967 Original Filed Jui 24, 1963 H. F. GREEN AIR TREATING ANDCONDITIONING APPARAIUS 7 Sheets-Sheet 6 I 44 77 a T INVENTOR. \(fd 7 T52 #4204 0 r. G/QEEA/ ATTORNEY y 4, 1967 H. F. GREEN 3,328,941

AIR TREATING AND CONDITIONING APPARATUS Original Filed July 24, 1963 '7Sheets-Sheet 7 United States Patent 3,328,941 AIR TREATING ANDCONDITIONING APPARATUS Harold F. Green, Rocky River, Ohio, assignor, bymesne assignments, to Space Conditioning, Inc., Harrisonburg, Va., acorporation of Maryland Continuation of application Ser. No. 297,335,July 24, 1963. This application June 30, 1966, Ser. No. 562,001 10Claims. (Cl. 55-234) This application is a continuation of my copendingapplication, Ser. No. 297,335, filed July 24, 1963, titled AirTreatingand Conditioning Apparatus, and now abandoned which applicationwas a continuation-in-part of application Ser. No. 111,966, filed May23, 1961, titled Method and Apparatus for Air Treatment, and nowabandoned.

This invention relates to an apparatus for treating air preparatory toits discharge into an occupied space, and particularly to an apparatusfor performing individually, or in selected combinations with eachother, any one or more of the operations of cleaning, deodorizing,cooling, humidifying, and dehumidifying, the air.

One of the principal objects of the present invention is to provide anair cleaning apparatus in which a new and improved air filter is drivenrepeatedly about a predetermined closed path, and, during its passagealong the path, each portion is caused to pass first through a bath ofwater or selected solution wherein it is washed by combined action ofthe bath and mechanical manipulation of the portion, then through adrain zone in which the water or solution is drained out to a degreesuch that only superficial films thereof remain on the portion, and thenthrough a nair cleaning zone in which a stream of air to be cleaned isblown through the filter and thereby cleaned by the filter and films,and, if desired, otherwise treated by the films, depending on thecomposition of the particular bath.

Another object is to control the apparatus automatically so that it canoperate efiiciently for prolonged periods without requiring servicing orthe attention of an operator.

Specific objects are to provide simple and eflicient devices forcontrolling the manner and speed of travel of the filter along its path,for maintaining the bath level and the proportions of the bathingredients within desirable ranges, and for removing from the bath theforeign matter which, 'having been removed from the air, is introducedinto the bath by the filter.

A more specific object is to provide a new and improved bath which notonly facilitates cleaning of the air, but also prolongs the life andimproves the quality and functioning of the filter.

Various other objects and advantages of the invention will becomeapparent from the following description wherein reference is made to thedrawings, in which:

FIG. 1 is a diagrammatic perspective view of an air treating apparatusembodying the principles of the present invention, combined with ahousehold heating furnace so as to employ the furnace air blower andduct system for circulating the air for cleaning and distribution;

FIG. 2 is an enlarged perspective view of the treating unit of FIG. 1,parts of the enclosing cabinet being broken away for clearness inillustration;

FIG. 3 is an enlarged fragmentary left side elevation of the upperportion of the apparatus illustrated in FIG. 2; part of the cabinet wallbeing broken away for clearness in illustration;

FIG. 4 is an enlarged fragmentary front elevation of the structureillustrated in FIG. 3, part of the cabinet wall being broken away;

FIG. 5 is an enlarged fragmentary left side elevation of the lowerportion of the apparatus illustrated in FIG. 2,

3,328,941 Patented July 4, 1967 part of the cabinet wall being brokenaway for clearness in illustration;

FIG. 6 is a fragmentary front elevation of the apparatus illustrated inFIG. 5;

FIG. 7 is an enlarged fragmentary side elevation of the apparatusshowing the lower portion of the filter immersed in a cleaning bath, anda means for manipulating the filter for cleaning it as it passes throughthe bath;

FIG. 8 is a front elevation of a motor driven sludge pump forming partof the present invention;

FIG. 9 is a top plan view of the pump illustrated in FIG. 8;

FIG. 10 is an enlarged fragmentary left end elevation of the apparatusshowing an intermittent timing device which is employed in automaticcontrol of the apparatus, the cover of the device being omitted;

FIG. 11 is a view of the apparatus of FIG. 10 as viewed on line 1111 inFIG. 10;

FIG. 12 is a wiring diagram showing the electrical connections which areemployed when it is desired to operate the treating apparatusautomatically;

FIG. 13 is an enlarged side elevation of a device for replenishingcertain ingredients in one of the solutions that may be used in thebath; and

FIG. 14 is an enlarged, fragmentary, perspective view showing the filtercombined with a device used for dehumidification.

Referring first to FIG. 1, the form of the apparatus shown for purposesof illustration is enclosed in a cabinet 1 which is disposed alongsidethe air jacket 2 of a domestic hot air furnace so as to take advantageof the existing recirculating motor driven blower 3, driven by anelectric motor 3a, and distribution duct system of the furnace forcirculation of air through the present apparatus and distributionthereof to selected locations in the house. If desired, the apparatusmay be equipped with its own blower and distribution system, or may bearranged to discharge directly into the space in which it is located,and operated independently of the furnace, if desired.

The furnace shown is a conventional one employing a heat exchanger 4over which air is blown by the blower 3. The air is discharged from thejacket 2 through a suitable outlet 5 into a conventional plenum chamberfrom which distribution ducts lead to the various rooms to be heated.

The rear wall of the air jacket 2 has an air inlet 6 through which aircan be drawn into the inlet of the blower 3.

The cabinet 1 has a front wall 7 with an outlet 8 nearv 11 so that theoutside air can be drawn into the inlet 10.

A damper 13 is provided for controlling the flow from the ducts 11 and12 so that all of the air to be treated can be recirculated room air, orall can be drawn in from the outside through the duct 12, as whencooling by evaporation is desired, or part can be outside air and partrecirculated air.

The cabinet 1 has 'a partition wall 14 which extends forwardly andrearwardly and divides the interior of thecabinet 1 into twocompartments one of which, designated 15, is connected to the outlet 8and inlet 10 and contains the filter mechanism. The other compartment,designated 16, contains the controls and power drives for the filter andtreating system.

Mounted within the compartment 15 is a filter 20 which is so arrangedthat substantially all of the air entering the inlet 10 must passthrough the filter in order to reach the outlet 8. The filter is onewhich is driven along a closed, generally upright path. Along the lowerportion of the path the filter passes through a suitable bath of water,or of a solution, wherein it is washed. At it rises above the path, partof the bath water, or solution, drains out leaving superficial films ofthe water or solution on the filter. Along a succeeding portion of itspath the filter, with these films thereon, is subjected to the airstream passing through the cabinet 1, after which it returns to the bathfor cleaning, followed by a repetition of the cycle.

For this purpose, the filter 20 preferably is an elongated sheet of thematerial which, at its ends, is provided with complementary zipperfastening means 21 by which the ends are connected together to providean endless belt but which can be unfastened to facilitate installationand removal. This belt is substantially coextensive, edgewise of thebelt, with the compartment and extends from near the top thereof to thelower portion.

An open top tank 22 is arranged in the compartment 15 just above theoutlet 8.

In order to support and drive the filter for movement along a closedpath wherein it passes into and out of the tank and across the airstream during its travel along a closed path, the filter is mounted on adriving roll 25 against which it is held for frictional driving by meansof an idler roll 26. The roll 25 is driven by a suitable electric motor27 The filter passes over suitable guide rolls 28, 29, 30 and 31 andbeneath a roll 32, these rolls holding and guiding it in proper positionrelative to the air stream.

The motor 27 is drivingly connected to the drive roll 25 through areduction gear train 35 which is directly connected to the shaft 36 ofthe roll 25. The idler roll 26 is supported on suitable pivoted links 37so that it can impose its own weight on the filter portion passing overthe roll 25. The motor 27 may be controlled in the first instance by ahumidistat 38 which can be set for the humidity desired or completelyturned off. Openings are provided connecting the compartments 15 and 16at both their upper and lower portions. Consequently, due to inbalanceair pressures in the compartment 15, air will flow upwardly ordownwardly in the compartment 16. The humidistat is preferably disposedbetween the upper and lower openings so that it will be quicklyresponsive to the relative humidity of the air which is treated. Ifintermittent drive is desired, the motor may also be made responsive toan intermitter control 40, as will later be described.

At its lower portion, where it passes beneath the roll 32, the filter isimmersed in a liquid bath in the tank 22. As its lower portion entersthe bath, the bath water or solution floods and washes the filter,dislodging much of the foreign matter therefrom. As the flooded portionpasses beneath the roll 32, and while immersed, the immersed portion isfirst squeezed so as to distort and compress it in the direction of itsthickness and discharge the water or solution. As it issues from beneaththe roll 32 it is released so as to draw in a fresh supply of the wateror solution from the bath preparatory to the thus cleaned portionissuing from the bath.

The \roll 32, therefore, provides a suitable compressing and releasingmeans for manipulating the filter in this manner.

In the illustrative example, the roll 32 is free floating and preferablyis weighted so that its weight, of itself, is enough to compress anddistort the belt in a direction of its thickness to at least half of itsnormal thickness as it passes beneath the roll 32. Thus the flooding,squeezing, release and re-expansion all occur while the portion of thebelt being cleaned is below the surface of the bath. As the portion thustreated rises from the bath, the water or solution drains very rapidlydownwardly from the filter, further flushing and cleaning it. As theportion continues to rise, in a very short space and time of movement,the residue of the bath water or solution remaining thereon issubstantially only superficial films coating strands of the filter.

The filter 20 is composed of a sheet of readily compressible, resilientand self-restoring, synthetic organic, foamed material of which the thinseptums or cell walls have been removed or eaten away chemically so thatthe final filter is a very open and porous three-dimensional skeletalframework of integrally interconnected strands which are readilydistortable elastically and immediately self-restoring. The filter hassubstantial thickness so that the strands can buckle and flex and thecells defined thereby can be readily changed in shape and distorted soas to squeeze out all of the bath solution except for superficial filmscoating the strands. This material, for brevity, as hereinafter referredto as skeletonized material. It has about 20 to 40 pores per linealinch, and preferably about thirty (30) pores per lineal inch, in each ofits three dimensions. The preferred material is composed of urethane,but other plastics having sufficient resiliency and readycompressibility may be employed.

The preferred material is one marketed as Scott Industrial Foam by ScottPaper Company of Chester, Pa.

This material has distinct advantages over other materials heretoforeknown. Due to its open structure, the uniformity of the pores, and thetensile strength of the strands, it retains its shape and assures arelatively free flow of air. Hence, as it enters the bath, the liquid ofthe bath penetrates fully and almost instantly, and hence can assist indislodging particles of foreign matter in the filter. All surfaces ofthe strands are readily accessible to the bath and can be flushedthereby. The filter is readily distortable by the pressure of the roll32 to expel the bath water or solution. Its almost instantaneousself-restoration, when relieved of the roll pressure, permits the inflowand full penetration of fresh water or solution from the bath.

Furthermore, due to the high degree of openness and porosity, and theabsence of closed cells which could entrap liquid it drains veryrapidly. This drainage reduces the weight to which the filter issubjected to such an extent that the filter is not elongated endwise ordistorted and contracted edgewise, as would be the case were all wallsintact so that myriad drops of water or solution were entrapped.Likewise, due to this effective drainage and openness of structure, thefilter offers very low resistanoe to the flow of air and it is notobjectionally bellied out and distorted at the portion currentlysubjected, in the direction of its thickness, to the air stream.

As mentioned, the filter 20 moves along a closed path. It must be opento receive the bath when it enters the bath. Next it must be compressedin the direction of its thickness so as to distort its entire crosssection and expel the liquid as it passes beneath the roll 32. Finallyit must be permitted to re-expand so that fresh liquid can flowtherethrough as it issues from beneath the roll 32. This .is illustratedin FIG. 7. Due to the very open nature of the skeletonized foamedmaterial, this compression and distortion of the material can beeffected by the roll 32 alone, as therein illustrated, though additionalsupplemental rolls can be provided for this purpose if desired, thespecific means for compression and release being secondary to the factthat compression is initiated and completed and re-expansion occurs allwhile the filter is immersed in the bath.

The filter in the form of an endless belt, as described, is preferredalso because it provides a better means for entrapping foreign particlesfrom the air stream passed therethrough. In effect, it filters the airtwice during each passage of the air through the cabinet 1. For example,the down-traveling portion of the belt, to the left in FIG. 7, firstintercepts the air stream and removes some of the foreign mattersuspended in the air. The air in passing through the upwardly risingportion, to the right in FIG. 7, is further cleaned, at even higherefliciency.

The superficial films remaining on the strands of the filter at thedownward travelling portion of the filter are adequate to assure thepick-up of particles from the air. The particles on this portion do nothave to remain adherent to the filter for long as they soon reach thebath where they are wetted and flushed out.

Due to the openness of the filter and the ready accessibility of thewater or solution in the bath to the surfaces of all of the strands,foreign particles collected on the filter, indicated generally by thedots F, are flushed out and settle to the bottom of the tank 22, asillustrated.

If desired, when the endless belt filter driven by the rolls isemployed, it is sometimes desirable to coat each edge of the filter, andthe margins of the front and rear faces of the filter adjacent theretowith a film latex or like resilient sealing material. The coating filmmay be sprayed on and is continuous, at each edge, from the inner limitof the front margin, around the edge to the inner limit of the rearmargin. This reinforces and strengthens the filter, thus assuring thatit is not stretched to an objectional degree vertically under the weightof the roll 32 and moisture burden and does not bend and spill air fromthe stream too rapidly over the edges, but, instead, assists inlocalizing any bellying of the belt to its central portion so that theair passes therethrough. As a result, less moisture is carried againstthe side walls of the casing at the ends of the filter. Furthermore, thecoating films so reduce, or eliminate, the porosity of the edges thatthe escape of water through the edges onto the cabinet is greatlyreduced. The coating at each edge is about two inches wideon the forwardface, and about one-half inch wide on the rear face. The edge itself islimited to the thickness of the belt which may be from about one-tenthof an inch, as shown in FIG. 7, to onehalf inch.

In addition, nylon traction tapes about an inch wide and coated withresilient plastic may be bonded on the filter near the edges, andpreferably on the rear face, for reducing wear on the filter due to thefriction drive, for reinforcing the belt against bellying, and formaintaining dimensional stability lengthwise of the filter.

With the structure thus far described, the bath used may be replenishedfrom time to time by removal of the tank 22, and cleaning, refilling andreplacing it.

If the present apparatus is to be made so as to be capable of performinga number of different selected air treating operations, means areprovided for controlling the travel of the filter accurately to meet thevarious conditions required.

Likewise, the bath in the reservoir may be plain water or a specialaqueous solution or other chemical bath, depending on the selectedtreating operations desired. In almost all instances, plain water or anaqueous solution is used. In either event, a certain amount of the wateris lost from the tank 22 during operation and has to be replaced. If thewater is to be replaced automatically, a suitable inlet pipe 41 isprovided and is connected to a suitable water source. The inlet pipe 41is connected, in turn, to a water level control which is in the form ofa suitable U-shaped inlet tube 42 supported in fixed position relativeto the cabinet 1. The tube has a discharge end 43 open upwardly. Thetank 22 is rockably supported at one end on a suitable fixed supportand, at the other end, is connected to a hanger 44. The hanger 44 issuspended from the lower end of a tension spring 45. The upper end ofthe spring 45 is connected to a bolt 46 pas-sing through a bracket 47which is secured in fixed relation to the cabinet 1. A wing nut 48 isprovided on the bolt 46 for manipulating the tension on the spring sothat it normally supports the tank in horizontal position when the tankis full, and lifts the connected end of the tank as the bath is reduced.

Mounted on the bracket 44 for movement therewith, and thereby with theadjacent end of the'tank 22, in a closure plug 49. When the tank isfilled to the proper level, it lowers sufliciently under the weight ofthe bath to cause the plug 49 to engage and close the upper dischargeend 43 of the tube 42 and thereby stop the flow of water. When the bathis subsequently reduced in volume, the spring 45 lifts the adjacent endof the tank 22 and with it the plug 49, thereby admitting water throughthe discharge end 43 of the tube 42. The regulation is such that thelevel of the bath in the tank 22 is kept a desired distance above thecenter of the roll 32 so that the portion of the filter currently in thebath can be squeezed or contracted and relieved and reexpanded to normalcondition while it is fully immersed in the bath.

A suitable roll retainer arm 50 may be connected to the bracket 47 andengage the roll 32 for prevening the displacement of the roll 32axially.

If desired, as illustrated in FIG. 6, the roll 32 may be hollow and openat both ends, and may be provided internally with an Archimedes screw 52extending about its inner periphery from one end to the other. The screwis such as to cause a gradual migration of the water or solution in theroll unidirectionally from one end of the roll 32 to the other as theroll 32 rotates.

With the level of the bath maintained in this manner, it is desirable toremove the foreign material from the reservoir automatically. For thispurpose, a drain tube 58 is provided. The drain tube 58 has at one endan inlet 59 disposed in the bottom of the tank 22, preferably at the endof the tank adjacent to the end in which the discharge 43 of the inlettube is disposed. This is desirable because foreign matter and sludgewill be urged to migrate toward the inlet 59 by the Archimedes screw inthe roll 32.

In general, the foreign matter removed from the filter in the bath tendsto settle to the bottom of the tank 22 and form a conglomerate slurry orsludge. This sludge accumulates very slowly and presents a removalproblem because a suflicient flow of water or solution out of thereservoir for transporting the sludge away would be impractical andwasteful. In order to remove such sludge without at the same timeremoving a disproportionate quantity of the bath, a motor driven pump 60is employed.

The pump 60 is of a specialized type and comprises a hollow casing 61having an inlet 62, an outlet 63, and an inner peripheral wall 64. Thewall 64 preferably is cylindrical. Rotatably mounted within the casing61 for rotation about an axis concentric with the wall 64 is a rotor 65on which are mounted a plurality of compression rollers 66. In the formillustrated, three rollers 66 are provided and are apart about therotational axis of the rotor 65. Extending into the inlet 62 into theexterior of the body 61, through the body, and out of the outlet 63, isa resilient self-restoring pumping tube 68. The tube 68 is connected atits inlet .end to the drain tube 58 and at its outlet end to a dischargetube 69 leading to a suitable sump or drain. The tube 68 passes aboutthe assemblage of rollers 66 in the interior of the casing 64. Theperipheries of the rollers are spaced relative to the inner peripheralwall 64 a distance such that the tube, of the wall thickness anddiameter employed, is compressed and completely closed at the locationscurrently passing between each roller 66 and the peripheral wall 64, andis released so that it restores itself to fully open condition at theportions currently between adjacent rollers and at the inlet and outlet.The rotor 65 is driven through a suitable speed reducer 70, connected tothe shaft 71 of the rotor 65, by an electric motor 72.

As a result of this compression and self-restoration, the pump is apositive displacement, pulsating, intermittent pump providing asystolic-diastolic action. Consequently, the sludge in the tube 68,between any two adjacent rollers 66, is entrapped and forced therealongfrom the inlet to the outlet and through the discharge tube 69 by aperistaltic action, and cannot return to the reservoir 22.

This type of pump has another distinct advantage. With it, the volume ofwater or solution pumped from the tank 22 can be controlled with greatprecision. Consequently, if any additives are to be added to the bath inminute ratios to the volume of the bath, the exact amount to be addedcan readily be predetermined and the additives fed to the bath inaccurately balanced ratios.

Furthermore, a pump of this character, that operates intermittently withpulsations, stirs the material in the drain tube 58 and the dischargetube 69 so as to prevent clogging of the tubes. Should any particles ofsubstantial size or any flake be entrapped in the sludge, it can readilybe transferred and positively forced by the sludge through the pump anddischarge tube, or broken up in the pump so that it can flow readilywith the sludge.

Preferably the tubes 58, 68 and 69 are of a resilient synthetic organicplastic having a naturally greasy surface to which foreign matter cannotreadily adhere.

The pump has a further advantage in that materials in the pump, when thepump is stopped for a period, cannot obtain sufficient air forappreciable evaporation which might tend to make them harden and clogthe pump.

The simplest embodiment of the invention is one wherein the bah in thetank 22 is water and is replenished by manually adding water to thetank, the tank being removed periodically, and cleaned, refilled, andreplaced. The blower 3 of the furnace may be turned on manually and runcontinuously for the cleaning periods desired. If cleaning only isdesired, the damper 13 may be set for recirculation of air in thebuilding.

If cooling by evaporation of the water is also desired, the damper 13 isset to admit air through the outside air duct 12 only. The air drawn infrom the outside and passed through the filter continuously is cleanedby the filter, but also cooled due to evaporation of the water on thefilter. This, of course, necessitates that a certain amount of moisturefrom the tank 22 be picked up by the outside air so that the airdischarged by the blower 3 is humidified. However, there is not acontinual accumulation and increase in relative humidity in the airinside of the building, as would be the case were the air recirculatedunder such conditions. Throughout many areas of the country, therelative humidity is so low that the amount of moisture added to the airby this operation is not such as to cause any inconvenience.

If less evaporation and cooling are desired, as when part 'or all of theair in the space is to be recirculated by opening the duct 11 andclosing the duct 12 in whole or part, the filter may be operatedintermittently. This is true also in other instances, as when it isdesirable to stress the cleaning of air without humidification, or whileheating in which case continuous admission of outside air in largequantities would be unduly expensive.

In all instances of use, it is desirable that the filter 20 be drivenvery slowly, and preferably intermittently, and the pump 60, if used, beoperated intermittently. For this purpose, the intermitter 40,heretofore referred to, is provided. As best illustrated in FIG. 11 and12, the intermitter 40 comprises a continuously driven electric motor 75of the electric clock type which, in turn, drives a speed reducer 76.The speed reducer drives a suitable output shaft 77 on which is mounteda cam disc 78 having an operating finger 79. A normally Ofi' switch 80,for controlling the filter drive motor 27, is provided. The switch 80has an operating lever 81 with which the finger 79 cooperates forturning the switch On. The output shaft 77 drives a speed reducer 82which, in turn, drives an output shaft 83. Mounted on, and forcorotation with, the shaft 83 is a cam disc 84 having an operatingfinger 85. A normally Otf switch 86 having an operating lever 87 whichis arranged to be operated by the finger 85 is provided for controllingthe pump motor 72.

The clock motor 75 and speed reducer 76 are such that the output shaft77 is normally driven at about one revolution per minute. The cam 78 issuch that the Ontime of the switch 80 is from two to four seconds perminute. The speed reducer 82 is such that it reduces the speed of thecam 84 to about one revolution per hour, and the cam 84 is such that theswitch 86 is held On approximately two minutes per hour.

As best illustrated in FIG. 12, the motor 3a of the furnace blower isconnected across a 110 volt A.C. source not shown, through one contactof a suitable manual switch 90, by leads L and L so that, if desired, itcan be kept On continuously for periods during which cooling isrequired. It may additionally be connected by a conventional thermostat,not shown, when the furnace is used for heating.

The humidistat 38 is connected in a circuit in series With the filterdrive motor 27 and another contact of the manual switch 90. This circuitis connected in parallel with the motor 3a across the leads L and L Thisplaces the filter motor 27 under the control of the humidistat while theblower 3 is operating. If the blower 3 is shut off, the motor 27 nolonger operates. If desired, the humidistat 38 may include a bypasscircuit including a normally open switch 93 which, when the humidistatis turned off, may be closed so that the motor 27 can operateindependently of the humidistat. Thus, if desired, the filter 20 may bedriven continuously so long as the blower 3 is operating. On the otherhand, the clock motor 75 of the intermitter 40 is connected across thelines L and L through a suitable manual switch 94, so that they areoperative independently of the humidistat.

The switch 80 is operative when closed to connect the filter drive motor27 across the lines L and L in bypassing relation to the humidistat 38so that the filter can be driven intermittently when the humidistat isOff.

The switch 86 is operative when closed to connect the pump motor 72across the source L and L so that the pump can be driven intermittentlyindependently of the humidistat. This arrangement has additionaladvantages when special solutions are employed for the bath in the tank22, as the delivery of the pump can be controlled very precisely, sothat the exact amount of replacement material to be added to the bathcan readily be determined. For example, the pump, driven by an 0.4ampere motor, can discharge from 0.01 cc. to cc. per pulsation andpreferably, when operated intermittently, 2 to 10 cc. per operation.

A particularly desirable solution is an aqueous hygroscopic solution andone containing, by weight, from about 5% to 7% glycerine is preferred.This percentage may be varied, depending on local conditionsfor example,from a minimum of 0.5% to 12% concentration.

With such a solution and intermittent drive, as the filter rises out ofthe bath, most of the solution drains back into the bath, futhercleaning and rinsing the filter beneath the drainage zone.

In the portion of the filter above the drainage Zone, before it entersthe air stream, the skeletal strands are coated with superficial filmsof the solution and the pores are open for relatively free passage ofair through the filter. As it is rising, the water in the superficialfilms is being evoparated, and when intermittent slow drive is employed,the fluid may be evaporated to equilibrium by the time the filter entersthe air stream. At this time, the superficial films, due to their lossof water, are very viscous and tacky, rather than dilute and highlyliquid, as in the tank 22. Hence they more readily entrap any suspendedmatter in the air, causing the suspended matter to adhere to the beltand the superficial tacky films thereon. Very minute particles arecoated and encapsulated with the viscous concentrate. In either event,they lose their airborne capacity and remain on the entrapping portionof the filter until it passes its upper limit of travel, moves down atthe opposite side of the rollers where it is again subject to the airand collects further foreign material, and is again washed by the bath.However, as the belt passes again into the bath, and is manipulated bythe roll 32, the viscous material is again diluted, becoming less tackyand freeing the accumulated foreign particles into the bath wherein theysettle gradually to the bottom of the tank 22 in the form of a sludge.Due to the solution in the bath, this sludge does not become dry andcaked, but remains in fluid condition so that it is withdrawn by thepump 60 through the tube 58. When the solution functions in this manner,it does not appreciably affect the humidity. If the filter is drivenrapidly, the solution in more dilute form is carried into the air streamand hence humidification and cleaning are combined.

In most cities, the water supply contains dissolved salts, such ascalcium and magnesium salts which, if water alone is used, would formscale in the reservoir and on the belt, thus stiffening the filter andtending to clog it in time. While this action is reduced greatly due tothe open structure of the present filter, to further improve theoperation, chelating agents for the salts in the water are provided.These chelating agents preferably are of the type for inhibiting theformation of scale by calcium and magnesium salts in the water, so thatthese salts become part of the sludge. However, these particular agentsused have an additional advantage in that, having once functioned toinhibit the scale formation by the water-dissolved salts, they remainchelating agents for airborne metallic oxides. Hence as these oxides areentrapped by the belt and brought into the bath, they are removed andbecome part of the sludge. Due to the glycerine in the bath, the sludgeremains soft and fluid enough to be pumped out by the pump 60 and in nocase are scale and the like precipitated.

The chelating agent preferably is one sold on the market as Versene 100,which is a trisodium salt of ethylene diamine tetra-acetic acid,marketed by the Dow Chemical Company of Midland, Mich. This salt ispreferred because it will complex the salt of almost any metal, whetherradio-active or not, to a water soluble complex that can be washed off.Versenex 80, an aqueous solution of pentasodiurn salt of diethylenetriamine penta-acetic acid is very effective, as also is Versanol 120, atrisodium salt of ethylene diamine tetra-acetic acid.

An effective solution is a formulation of 8% Versene 100, 92% glycerine,diluted to an aqueous solution of concentration. About 80 fluid ouncesof the aqueous solution fill the tank 22. Usually about 20 cc. per hourare removed by the pump. The loss is made up by the automatic additionof water, as described. About four additional ounces of the undilutedsolution is added to the bath each week for replacement. This maintainsthe concentration of glycerine from about 5% to about 7.2%.

The solution referred to has another distinct advantage, when used as aninitial treatment for coating the filter even through the filter is tobe used subsequently only with water. It has been found that the coatingof the filter with the aqueous solution of glycerine, greatly prolongsthe life. This appears to be due to the fact that the solution ishygroscopic and inhibits or prevents drying of the filter and theglycerine lubricates the filter and tends to keep it in soft andresilient condition. The chelating agents tend to neutralize reaction ofthe alkaline salts in the water with the urethane. When so coated, thefilter retains sufficient moisture so that the entrapped material on itdoes not form hard crusts and deposits.

In order to inhibit the growth of germs, bacteria, fungi, algae, andother odor causing forms, an antiseptic chemical is added to the bath.Preferably, the chemical used is a quaternary ammonium which isdesirable in that it is non-volatile, and aids washing, and is composedmolecularly of long waxy chains which increase the tensile strength ofthe urethane fibers of the filter. A desirable one is n-alkyl dimethyl,benzylammonium chloride, which, in concentrations of 200 ppm. can kill99.999% of test face at the up-travelling organisms commonly used fortesting the efficacy of such compositions. The bath solution, asmentioned, is concentrated, due to evaporation, before it passes throughthe forced air stream. Hence the quaternary ammonium salts areconcentrated to as much as 600 ppm, thus rendering them very effectiveexactly where subjected to the air stream. This chemical is effectiveboth for deodorizing and sanitizing the air.

To introduce antiseptic materials automatically, at very simplestructure, such as illustrated in FIG. 13, may be provided. Preferablythe antiseptic solution is supplied in a disposable bottle 95, having adischarge tube 96, through which the antiseptic is to be discharged. Thetube 96 is arranged to drain into the upper end of a reservoir 97. Thereservoir 97 fits in sealed relation about the tube 96 and itselfdischarges through a suitable metering nozzle 98. The nozzle 98preferably is in the form of a hypodermic needle having an extremelysmall discharge opening so that the feed of the solution from thereservoir 97 is in the form of successive minute drops. The drops passinto a small tube 99 leading to the tank 22. The tube 99, between itsends, is normally held shut by a spring-pressed finger 100 which isintermittently released for short intervals by the cam which controlsthe motor of the pulsating pump. With this arrangement, the antisepticis fed to the tank in direct proportion to discharge by the pump 60.Since this discharge of the pump 60 is very precisely metered, due tothe nature of the pump, the amount of antiseptic to be added can beaccurately controlled. For instance, the needle can be selected so that60 droplets are equal to about 1 cubic centimeter. Since the intermitteris such that it operates the pump only once every hour, and then not formore than two minutes, the drip from the nozzle can be controlled sothat very few droplets per hour are fed to maintain the proper ratio ofantiseptic to tank solution.

Again, in some instances, as illustrated in FIG. 14, it may be desirableto dehumidify the air. In those instances, a combined heater and blowerunit 101 may be used. The unit includes an infra-red or radiant heater101a disposed between the up-travelling and down-travelling portions ofthe filter, and exposed toward the inner face of the up-travellingportion of the filter for heating the solution therein. The unit alsoincludes an elongated duct 102 having an inlet extending across thewidth of the outer portion of the filter. Air is drawn through thefilter from the face opposite from the infrared heater and discharged tothe outside atmosphere,

by means of a motor driven suction fan 103. With this' arrangement, thewater in the solution on the filter 20 can be greatly reduced andexpelled to the outside of the building, whereupon, when the filterpasses through the air stream being recirculated in the building, thehydroscopic material can remove a much greater amount of the moisturefrom the air.

This operation can be continued until the moisture content of the air isreduced to the desired level.

Preferably the filter material is, as mentioned, urethane, which hasspecific advantages over synthetic organic plastics, but in someinstances, other synthetic organic plastic foam material may be used,but it must be skeletonized for proper operation.

It is apparent, therefore, that with the above described apparatus, alarge number of treatments can be administered to the air, selectively,successively, or concurrently, in different combinations, and thatapparatus of limited use for performing only one or less than all of thetreatments may be provided based on the principles disclosed.

Having thus described my invention, I claim:

1. An apparatus for the treatment of air and comprising an enclosure,upper and lower horizontal rolls therein, at least one of said rollsbeing a drive roll, means for driving the drive roll unidirectionally atvery slow speed, an endless filter belt extending about the rolls andsup ported thereby and driven by the drive roll along a closed pathwherein the inner face of the downwardly traveling portion of the beltis in spaced face to face relation to the inner face of the upwardlytraveling portion of the belt, said enclosure having an inlet and anoutlet, means to blow air into the inlet, means to direct the air blowninto the inlet to enter the belt through the outer face of the belt atthe downwardly traveling portion of the belt, then pass through bothportions of the belt, and out through the upwardly traveling portion sothat the air discharges finally through the outer face of the upwardlytraveling portion;

said filter belt being a compressible and distortable,

resilient, self-restoring, three dimensional, open porous skeletalframework of interconnected strands of synthetic organic plasticmaterial, and said framework being of substantial thickness so that,upon buckling and fiexure of the strands of the framework, the frameworkis reduced in thickness and the open pores are changed in shape andreduced in size and, upon discontinuance of the buckling and flexure,the framework is self-restored to its original thickness and the poresare self-restored to their original shape;

said open pores providing a multiplicity of relatively freeinterconnected passages extending through the filter belt and of a sizeaffording a relatively free flow of air directly through the filterbelt;

said lower roll being arranged to apply force downwardly against theinner face of the belt, at the lower portion of the 'belt, sufficient tobuckle and flex the strands of the belt and thereby materially reducegradually the thickness of the belt from the normal thickness it had asit approached the lower roll, and then to gradually release the force asthe belt passes out from beneath the lower roll so that the beltrestores itself to its normal thickness and the pores restore themselvesto their original open shape; and means, including a tank, formaintaining a liquid bath through which the portion of the belt which isin contact with the lower roll is constrained to pass while said portionis in contact with said lower roll.

2. The apparatus according to claim 1 wherein a power driven positivedisplacement sludge pump is provided and comprises an inlet connectedwith the tank and an outlet connected to a sump, a resilient tubeconnecting the inlet to the outlet, and pressure applying means forcausing collapse of the tube followed by release thereof in a migratoryzone progressing repeated unidirectionally from the inlet toward theoutlet to provide a systollicdiastolic pumping action.

3. The apparatus according to claim 2 wherein the pressure applyingmeans comprises a casing having a wall extending lengthwise of the tubeand against which the tube can be pressed for collapsing it, and aseries of rollers in spaced relation to each other endwiseunidirectionally of the tube, means to drive the rollers endwise of thewall, and said rollers being spaced from the wall so that each collapsesthe tube progressively at the portion between the periphery of theroller and the wall, and then to release it, as the roller progressesalong the wall.

4. The apparatus according to claim 2 wherein the pump is driven by anelectric motor, and intermitter means are provided for causing the pumpmotor to operate intermittently.

5. The apparatus according to claim 4 wherein drip feed means areprovided for supplying additives to the tank in precise relation to thevolumetric discharge of the pump.

6. The apparatus according to claim 5 wherein control means normallyprevent the additives which drip from the feed means from flowing backto the tank, and means interconnect the intermitter means and control 12means to cause the control means to permit said flow of additives whenthe pump is operating.

7. An apparatus according to claim 1 wherein the bath is a dilutehygroscopic solution, and means are provided for controlling the poweroperated means so as to drive the filter belt along the upward portionof its path at a very slow rate for permitting any free solution todrain from the filter belt along the initial portion of said upwardportion of the path and which permits substantial reduction of the watercontent of the films by the time they reach the downwardly travelingportion of the path, thereby to increase their viscosity.

8. The structure according to claim 1 wherein the outer face of the beltis unconfined while the belt is in contact with the lower roll.

9. The structure according to claim 1 wherein the apparatus is free frommeans for applying liquid to the belt while the belt is out of saidbath.

10. An apparatus for the treatment of air and comprising an enclosure,upper and lower horizontal rolls therein, at least one of said rollsbeing a drive roll, means for driving the drive roll unidirectionally atvery slow speed, an endless filter belt extending about the rolls andsupported thereby and driven by the drive roll along a closed pathwherein the inner face of the downwardly traveling portion of the beltis in spaced face to face relation to the inner face of the upwardlytraveling portion of the belt, said enclosure having an inlet and anoutlet, means to blow air into the inlet, means to direct the air blowninto the inlet to enter the belt through one of said portions of thebelt, then pass through both portions of the belt, and out through theother of said portions;

said filter belt being a compressible and distortable,

resilient, self-restoring, three dimensional, open porous skeletalframework of interconnected strands of synthetic organic plasticmaterial, and said frame work being of substantial thickness so that,upon buckling and flexure of the strands of the framework, the frameworkis reduced in thickness and the open pores are changed in shape andreduced in size and, upon discontinuance of the buckling and fiexure,the framework is self-restored to its original thickness and the poresare self-restored to their original shape;

said open pores providing a multiplicity of relatively freeinterconnected passages extending through the filter belt and of a sizeaffording a relatively free flow of air directly through the filterbelt;

said lower roll being arranged to apply force downwardly against theinner face of the belt, at the lower portion of the belt, sufiicient tobuckle and flex the strands of the belt and thereby materially reducegradually the thickness of the belt from the normal thickness it had asit approached the lower roll, and then to gradually release the force asthe belt passes out from beneath the lower roll so that the beltrestores itself to its normal thickness and the pores restore themselvesto their original open shape; and

means, including a tank, for maintaining a liquid bath through which theportion of the belt which is in contact with the lower roll isconstrained to pass while said portion is in contact with said lowerroll.

References Cited UNITED STATES PATENTS 1,757,690 5/1930 Strindberg55-492 1,888,001 11/1932 Hicks 261 1,949,540 3/1934 Hammond 261-801,970,301 8/1934 Frankel 26l80 1,976,401 10/1934 Ilg 55353 (Otherreferences on following page) 13 UNITED STATES PATENTS Langford 261-84Fleisher 261-24 Culpepper 55-272 Ortiges 55-229 Fleisher 55-228 Hetzel210-401 Lowery 210-198 Rochlin 55-502 Rice 261-80 1 Morrison 210-401Revell 55-233 Coleman 55-279 Boylan 55-233 FOREIGN PATENTS 2/ 1914Austria.

HARRY B. THORNTON, Primary Examiner. 0 D. TALBERT, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,328,941 July 4 1967 Harold F. Green It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 1 line 34 for "a nair" read an air column 4 line 30 after"matter" insert carried column 5 line 75 for "in" read is column 6 line15 for prevenlng" read preventing column 7 line 25 for bah" read bathcolumn 8 line 55 for "futher" read further line 62 for "evoparated" readevaporated column 9 line 55 for "through" read though Signed and sealedthis 15th day of October 1968 (SEAL) Attest: Edward M. Fletcher, Jr.EDWARD J. BRENNE:

Attesting Officer Commissioner of Patent!

1. AN APPARATUS FOR THE TREATMENT OF AIR AND COMPRISING AN ENCLOSURE,UPPER AND LOWER HORIZONTAL ROLLS THEREIN, AT LEAST ONE OF SAID ROLLSBEING A DRIVE ROLL, MEANS FOR DRIVING THE DRIVE ROLL UNIDIRECTIONALLY ATVERY SLOW SPEED, AN ENDLESS FILTER BELT EXTENDING ABOUT THE ROLLS ANDSUPPORTED THEREBY AND DRIVEN BY THE DRIVE ROLL ALONG A CLOSED PATHWHEREIN THE INNER FACE OF THE DOWNWARDLY TRAVELING PORTION OF THE BELTIS IN SPACED FACE TO FACE RELATION TO THE INNER FACE OF THE UPWARDLYTRAVELING PORTION OF THE BELT, SAID ENCLOSURE HAVING AN INLET AND ANOUTLET, MEANS TO BLOW AIR INTO THE INLET, MEANS TO DIRECT THE AIR BLOWNINTO THE INLET TO ENTER THE BELT THROUGH THE OUTER FACE OF THE BELT ATTHE DOWNWARDLY TRAVELING PORTION OF THE BELT, THEN PASS THROUGH BOTHPORTIONS OF THE BELT, AND OUT THROUGH THE UPWARDLY TRAVELING PORTION SOTHAT THE AIR DISCHARGES FINALLY THROUGH THE OUTER FACE OF THE UPWARDLYTRAVELING PORTION; SAID FILTER BELT BEING A COMPRESSIBLE ANDDISTORTABLE, RESILIENT, SELF-RESTORING, THREE DIMENSIONAL, OPEN POROUSSKELETAL FRAMEWORK OF INTERCONNECTED STRANDS OF SYNTHETIC ORGANICPLASTIC MATERIAL, AND SAID FRAMEWORK BEING OF SUBSTANTIAL THICKNESS SOTHAT, UPON BUCKLING AND FLEXTURE OF THE STRANDS OF THE FRAMEWORK, THEFRAMEWORK IS REDUCED IN THICKNESS AND THE OPEN PORES ARE CHANGED INSHAPE AND REDUCED IN SIZE AND, UPON DISCONTINUANCE OF THE BUCKLING ANDFLEXURE, THE FRAMEWORK IS SELF-RESTORED TO ITS ORIGINAL THICKNESS ANDTHE PORES ARE SELF-RESTORED TO THEIR ORIGINAL SHAPE; SAID OPEN PORESPROVIDING A MULTIPLICITY OF RELATIVELY FREE INTERCONNECTED PASSAGESEXTENDING THROUGH THE FLITER BELT AND OF A SIZE AFFORDING A RELATIVELYFREE FLOW OF AIR DIRECTLY THROUGH THE FILTER BELT; SAID LOWER ROLL BEINGARRANGED TO APPLY FORCE DOWNWARDLY AGAINST THE INNER FACE OF THE BELT,AT THE LOWER PORTION OF THE BELT, SUFFICIENT TO BUCKLE AND FLEX THESTRANDS OF THE BELT AND THEREBY MATERIALLY REDUCE GRADUALLY THETHICKNESS OF THE BELT FROM THE NORMAL THICKNESS IT HAD AS IT APPROACHEDTHE LOWER ROLL, AND THEN TO GRADUALLY RELEASE THE FORCE AS THE BELTPASSES OUT FROM BENEATH THE LOWER ROLL SO THAT THE BELT RESTORES ITSELFTO ITS NORMAL THICKNESS AND THE PORES RESTORE THEMSELVES TO THEIRORGINAL OPEN SHAPE; AND MEANS, INCLUDING A TANK, FOR MAINTAINING ALIQUID BATH THROUGH WHICH THE PORTION OF THE BELT WHICH IS IN CONTACTWITH THE LOWER ROLL IS CONSTRAINED TO PASS WHILE SAID PORTION IS INCONTACT WITH SAID LOWER ROLL.